1. Field of the Invention
The present invention relates to a communication apparatus which selects a communication protocol compatible to a partner station and executing the selected protocol.
2. Related Background Art
In prior art apparatus of this type, a facsimile apparatus is known. The communication protocol of the facsimile apparatus includes G1, G2, G3 and G4 protocols. The G4 protocol uses a digital line and the G1, G2 and G3 protocols use an analog public line. In connecting a line to a communication partner station, the facsimile apparatus sequentially sends the G3 protocol, the G2 protocol and the G1 protocol and determines which protocol is to be executed in accordance with the presence or absence of acknowledge signals to the respective sent signals.
However, in the above facsimile apparatus, the G3 protocol, the G2 protocol and the G1 protocol are sequentially sent and the presence or absence of the acknowledge signal thereto is checked. Accordingly, a long time is required before the communication protocol to be executed is determined.
When a new communication protocol is added to the above protocols, a longer time is required before the communication protocol is determined. Where signals are to be sent and received to and from the partner station, if the reception of the signal is unsuccessful, a protocol of a lower function is selected even if the partner station actually has a protocol of a higher function.
Information on the communication function of the partner station may be registered, together with a telephone number of the partner station, in a one-touch dial key or an abbreviated dial key. Thus, when a call is made by depressing the dial key, the communication mode is selected in accordance with the registered information of the communication function (U.S. Pat. No. 4,910,506).
However, in the above U.S. Pat. No. 4,910,506, the information of the communication function registered in the one touch key is not useful for a received call.